Integrated biogeochemical and hydrologic processes driving arsenic release from shallow sediments to groundwaters of the Mekong delta   总被引：3，自引：0，他引：3  

Benjamin D. Kocar  Matthew L. Polizzotto  Shawn G. Benner  Samantha C. Ying  Mengieng Ung  Kagna Ouch  Sopheap Samreth  Bunseang Suy  Kongkea Phan  Michael Sampson  Scott Fendorf 《Applied Geochemistry》2008

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Physical and numerical studies of stability of soil blocks reinforced by brittle shear pins     

Ukritchon  Boonchai  Ouch  Rithy  Pipatpongsa  Thirapong  Khosravi  Mohammad Hossein 《Acta Geotechnica》2019,14(6):2103-2122

In this paper, the stability and failure mechanism of soil blocks that were reinforced by brittle shear pins and rested on a low-interface friction plane were studied by means of physical and numerical models. The humid silica sand no. 6 was employed to build the physical models of soil blocks, while the Teflon sheet was employed as the low-interface friction plane. To study the effect of stabilizing piles on slopes, the soil blocks were reinforced by brittle shear pins using pencil leads with 2 mm in diameter. Three-dimensional finite element analyses were employed to analyze the stability of this problem. The effects of numbers and patterns of shear pins on the stability and failure mechanisms of physical and numerical models were compared and discussed.

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Groundwater flow in an arsenic-contaminated aquifer,Mekong Delta,Cambodia     

Shawn G. Benner  Matthew L. Polizzotto  Benjamin D. Kocar  Somenath Ganguly  Kongkea Phan  Kagna Ouch  Michael Sampson  Scott Fendorf 《Applied Geochemistry》2008

To advance understanding of hydrological influences on As concentrations within groundwaters of Southeast Asia, the flow system of an As-rich aquifer on the Mekong Delta in Cambodia where flow patterns have not been disturbed by irrigation well pumping was examined. Monitoring of water levels in a network of installed wells, extending over a 50 km² area, indicates that groundwater flow is dominated by seasonally-variable gradients developed between the river and the inland wetland basins. While the gradient inverts annually, net groundwater flow is from the wetlands to the river. Hydraulic parameters of the aquifer (K ≈ 10⁻⁴ ms⁻¹) and overlying clay aquitard (K ≈ 10⁻⁸ ms⁻¹) were determined using grain size, permeameter and slug test analyses; when coupled with observed gradients, they indicate a net groundwater flow velocity of 0.04–0.4 ma⁻¹ downward through the clay and 1–13 ma⁻¹ horizontally within the sand aquifer, producing aquifer residence times on the order 100–1000 a. The results of numerical modeling support this conceptual model of the flow system and, when integrated with observed spatial trends in dissolved As concentrations, reveal that the shallow sediments (upper 2–10 m of fine-grained material) are an important source of As to the underlying aquifer.  相似文献